Many users may maintain user centric data with various services. In an example, a user may maintain an email contact list with a personal email service accessible through a personal email app and/or a personal email website. In another example, a user may maintain a work calendar with a work productivity service. The work calendar may comprise event data, calendar entries, tasks, email data, and/or a variety of other user centric data. In another example, a user may maintain a social network profile with a social network service. The social network profile may correspond to a social network friend list, social network messages, a social network calendar, social network profiles, social network posts, and/or a variety of other user centric data. Such services may be accessible through apps, such as the personal email app, a social network app, a work productivity app, etc. Aggregating and/or sharing user centric data between apps may be useful, but may pose security and/or privacy risks (e.g., a spam application may utilize personal information exposed by another app to spam other users or cause other problems).